Spectroscopic studies on the higher binary fluorides of chromium: CrF4, CrF5, and CrF6, both in the solid state and isolated in inert gas matrices

Hope, Eric G.; Jones, P. J.; Levason, William; Ogden, J. S.; Tajik, Mahmoud; Turff, J. W.

doi:10.1039/dt9850001443

“…Co-crystallized CrOF4 is introduced into the coordination sphere of [CrOF5] 2upon crystallization (see compound (6), X-ray Crystallography).…”

Section: Synthesesmentioning

confidence: 99%

“…Quantum-chemical calculations were employed to aid in the vibrational frequency assignments and to assess the bonding in several key compounds. (6). The room-temperature reaction of equimolar mixtures of XeF6 and CrOF4 was initially accompanied by vigorous gas evolution and the formation of a dark purple liquid (eq 4).…”

Section: Introductionmentioning

confidence: 99%

Chromium Oxide Tetrafluoride and Its Reactions with Xenon Hexafluoride; the [XeF5]+ and [Xe2F11]+ Salts of the [Cr(VI)OF5]–, [Cr(IV)F6]2–, [Cr(V)OF5]2–, and [Cr(V)2O2F8]2– Anions

Stuart¹,

Bortolus²,

Goettel³

et al. 2018

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0

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Molten mixtures of XeF6 and CrVIOF4 in 1:1 and 1:2 molar ratios undergo reduction to Cr(V) and Cr(IV) by means of F2 elimination to form [XeF5][Xe2F11][CrVOF5]∙2CrVIOF4 and [XeF5]2[CrIVF6]∙2CrVIOF4, respectively, as shown by low-temperature (LT) single-crystal X-ray diffraction (SCXRD). A LT Raman spectroscopic study of an equimolar mixture of solid XeF6 and CrOF4 and its melt showed that [CrVIOF5]– is formed as an intermediate. Reaction of [XeF5]2[CrIVF6]∙2CrVIOF4 with XeF6 in a melt gave [Xe2F11]2[CrIVF6] and [XeF5]2[CrV2O2F8]. Their LT crystal structures revealed that [XeF5]+ and [Xe2F11]+ are coordinated to their respective [CrF6]2− and [Cr2O2F8]2− anions by means of Xe---F–Cr bridges to form infinite chain structures. The reactions of a 1:1 molar ratio of XeF6 and CrOF4 in anhydrous hydrogen fluoride (aHF) and in mixed CFCl3/aHF solvents yielded [XeF5]2[CrV2O2F8]∙2HF and a mixture of [XeF5]2[CrV2O2F8]∙2HF and [XeF5]2[CrV2O2F8]∙2XeOF4, respectively. The SCXRD structures of the latter and aforementioned salts provide the first X-ray structures of [CrOF5]2– and [Cr2O2F8]2–. The [XeF5]2[CrV2O2F8]∙2XeOF4 and [XeF5][Xe2F11][CrVOF5]∙2CrVIOF4 salts were also characterized by LT Raman spectroscopy. Quantum-chemical calculations were carried out to obtain the energy-minimized, gas-phase geometries and vibrational frequencies for [CrVIOF5]–, [XeF5]2[CrV2O2F8]∙2XeOF4, [CrV2O2F8]2–, [XeF5][Xe2F11][CrVOF5]∙2CrVIOF4, [CrVOF5]2–, and to aid in the assignments of their vibrational frequencies.

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“…Additional Cr---F interactions occur between the CrOF4 molecule and the fluorine atoms of 5, Tables S2 and S6). (6) do not form extended structures, but consist of well-isolated formula units having no significant intermolecular interactions with one another (Figures 5, 6, S6, and S7).…”

Section: Synthesesmentioning

confidence: 99%

Chromium Oxide Tetrafluoride and Its Reactions with Xenon Hexafluoride; the [XeF5]+ and [Xe2F11]+ Salts of the [Cr(VI)OF5]–, [Cr(IV)F6]2–, [Cr(V)OF5]2–, and [Cr(V)2O2F8]2– Anions

Dg¹,

Mr²,

Goettel³

et al. 2018

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0

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Molten mixtures of XeF6 and CrVIOF4 in 1:1 and 1:2 molar ratios undergo reduction to Cr(V) and Cr(IV) by means of F2 elimination to form [XeF5][Xe2F11][CrVOF5]∙2CrVIOF4 and [XeF5]2[CrIVF6]∙2CrVIOF4, respectively, as shown by low-temperature (LT) single-crystal X-ray diffraction (SCXRD). A LT Raman spectroscopic study of an equimolar mixture of solid XeF6 and CrOF4 and its melt showed that [CrVIOF5]– is formed as an intermediate. Reaction of [XeF5]2[CrIVF6]∙2CrVIOF4 with XeF6 in a melt gave [Xe2F11]2[CrIVF6] and [XeF5]2[CrV2O2F8]. Their LT crystal structures revealed that [XeF5]+ and [Xe2F11]+ are coordinated to their respective [CrF6]2− and [Cr2O2F8]2− anions by means of Xe---F–Cr bridges to form infinite chain structures. The reactions of a 1:1 molar ratio of XeF6 and CrOF4 in anhydrous hydrogen fluoride (aHF) and in mixed CFCl3/aHF solvents yielded [XeF5]2[CrV2O2F8]∙2HF and a mixture of [XeF5]2[CrV2O2F8]∙2HF and [XeF5]2[CrV2O2F8]∙2XeOF4, respectively. The SCXRD structures of the latter and aforementioned salts provide the first X-ray structures of [CrOF5]2– and [Cr2O2F8]2–. The [XeF5]2[CrV2O2F8]∙2XeOF4 and [XeF5][Xe2F11][CrVOF5]∙2CrVIOF4 salts were also characterized by LT Raman spectroscopy. Quantum-chemical calculations were carried out to obtain the energy-minimized, gas-phase geometries and vibrational frequencies for [CrVIOF5]–, [XeF5]2[CrV2O2F8]∙2XeOF4, [CrV2O2F8]2–, [XeF5][Xe2F11][CrVOF5]∙2CrVIOF4, [CrVOF5]2–, and to aid in the assignments of their vibrational frequencies.

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“…Ausgangspunkt unserer Untersuchungen waren neuere Arbeiten, nach denen CrF6 sowohl aus Cr03 und 25 bar F, bei 170°C als auch durch Disproportionierung von CrF, bei niedrigen Driicken entstehen sol1 5,6 Die …”

Section: Spectroscopic Studies Of Higher Chromium Fluorides Controveunclassified

Spektroskopische Studien an höheren Chromfluoriden. Zur Frage der Existenz von Chromhexafluorid, CrF₆

Jacob¹,

Willner

²

1990

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Spectroscopic Studies of Higher Chromium Fluorides. Controversy over the Existence of Chromium Hexafluoride, CrP6 Combustion of chromium with fluorine under various conditions led always to CrF5 as the highest chromium fluoride. The properties of pure CrF5 have been reinvestigated and IR, UV spectra of the gas‐phase molecule, and also the vapor pressure have been measured for the first time. Furthermore, it has been shown that the IR spectrum of matrix‐isolated CrF5 is identical to the IR spectrum of CrF6 quoted in the literature. It appears, that in principle the existence of CrF6 is doubtful.

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Spectroscopic studies on the higher binary fluorides of chromium: CrF4, CrF5, and CrF6, both in the solid state and isolated in inert gas matrices

Cited by 34 publications

References 2 publications

Chromium Oxide Tetrafluoride and Its Reactions with Xenon Hexafluoride; the [XeF5]+ and [Xe2F11]+ Salts of the [Cr(VI)OF5]–, [Cr(IV)F6]2–, [Cr(V)OF5]2–, and [Cr(V)2O2F8]2– Anions

Chromium Oxide Tetrafluoride and Its Reactions with Xenon Hexafluoride; the [XeF5]+ and [Xe2F11]+ Salts of the [Cr(VI)OF5]–, [Cr(IV)F6]2–, [Cr(V)OF5]2–, and [Cr(V)2O2F8]2– Anions

Chromium Oxide Tetrafluoride and Its Reactions with Xenon Hexafluoride; the [XeF5]+ and [Xe2F11]+ Salts of the [Cr(VI)OF5]–, [Cr(IV)F6]2–, [Cr(V)OF5]2–, and [Cr(V)2O2F8]2– Anions

Spektroskopische Studien an höheren Chromfluoriden. Zur Frage der Existenz von Chromhexafluorid, CrF₆

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Spectroscopic studies on the higher binary fluorides of chromium: CrF4, CrF5, and CrF6, both in the solid state and isolated in inert gas matrices

Cited by 34 publications

References 2 publications

Chromium Oxide Tetrafluoride and Its Reactions with Xenon Hexafluoride; the [XeF5]+ and [Xe2F11]+ Salts of the [Cr(VI)OF5]–, [Cr(IV)F6]2–, [Cr(V)OF5]2–, and [Cr(V)2O2F8]2– Anions

Chromium Oxide Tetrafluoride and Its Reactions with Xenon Hexafluoride; the [XeF5]+ and [Xe2F11]+ Salts of the [Cr(VI)OF5]–, [Cr(IV)F6]2–, [Cr(V)OF5]2–, and [Cr(V)2O2F8]2– Anions

Chromium Oxide Tetrafluoride and Its Reactions with Xenon Hexafluoride; the [XeF5]+ and [Xe2F11]+ Salts of the [Cr(VI)OF5]–, [Cr(IV)F6]2–, [Cr(V)OF5]2–, and [Cr(V)2O2F8]2– Anions

Spektroskopische Studien an höheren Chromfluoriden. Zur Frage der Existenz von Chromhexafluorid, CrF6

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Spektroskopische Studien an höheren Chromfluoriden. Zur Frage der Existenz von Chromhexafluorid, CrF₆